Please reference to FIGS. 6 and 7, the conventional adjustable belt buckle 200 is illustrated. A binding belt 230 is passed through a main body 210 and a single-tooth portion 220 arranged inside the main body 210 may be engaged with a multi-teeth portion 240 of the binding belt 240.
However, the conventional adjustable belt buckle 200 only uses the single-tooth portion 220 to engage with the multi-teeth portion 230. The engagement between the single-tooth portion 220 and the multi-teeth portion 240 is week. It is easy to result in the damage of the single-tooth portion 220 while forcing the binding belt 230 excessively.